1. Field of the Invention
This invention is broadly directed toward a square baler having a reciprocating plunger with spaced apart crop compacting and bale forming elements, and particularly concerns a series of shiftable cleanout probes which are movable through interior regions of the plunger for removal of loose crop materials which might otherwise be carried upwardly by knotting needles and become entangled in an overhead knotting device.
2. Description of the Prior Art
Balers for producing square bales of hay typically have an elongated chamber and a plunger shiftably mounted within the chamber for compaction of crop materials and formation of a bale. The plunger of such balers moves through an operating cycle which comprises a retraction stroke away from a partially formed bale in the chamber for enabling the admission of additional crop materials into the chamber between the plunger and the partially formed bale, followed by a compaction stroke to compress the newly admitted materials into compacted relation with the rest of the bale. Once a sufficient amount of crop materials have been introduced into the chamber and the bale is fully formed, a plurality of needles carry strands of baling twine, wire or the like around the end of the bale adjacent the plunger and then a knotting mechanism ties ends of the strands together to thereafter retain the bale in its compacted, formed configuration.
Typically, plungers of square balers are comprised of a series of elements each presenting a crop engaging and compacting face, and the elements are mounted on a frame member that extends transversely across the baling chamber for coupling each of the elements to a reciprocating drive mechanism. The elements are spaced apart from each other along the length of the frame member in order to provide clearance openings between each adjacent pair of elements, so that the needles carrying the baling twine or wire can pass through the space between the elements and allow the twine to be tied around the bale while the plunger is extended to maintain the bale in its compacted condition.
In smaller square balers, the crop engaging face of the plunger is often constructed to present two slots of relatively narrow width for enabling the needles to pass through the plunger and up toward the knotting device. In some cases, the slots of smaller balers become clogged with crop material and impede the needles as they move through the slots, occasionally breaking the needles or bending the needles away from the knotter. To overcome this problem, a pair of stationary cleanout probes of the type described in U.S. Pat. No. 4,604,858 and assigned to the assignee of the present invention may be fixed to walls defining the bale chamber for telescopic reception within the slots of the plunger during each retraction stroke thereof, to prod and poke loose materials from the plunger that might otherwise collect within the slots.
In larger square balers, and particularly those capable of producing bales having a weight of about one ton, the width of openings between adjacent elements of the plunger is somewhat larger than the width of the clearance slots in smaller balers, and consequently the crop materials do not normally become tightly compacted between the elements of the plunger of larger balers to such a degree that would cause the twine carrying needles to deflect or break. However, loose crop materials sometimes collect on top of the horizontal plunger frame members supporting the elements and as a result the needles when passing through the spaces between the elements may catch a portion of the crop materials and carry the same up to the knotting device. Thereafter, the knotting device may become so entangled with the crop materials that satisfactory operation of the knotter and binding of the bale is precluded.